Protector bubble cancels itself if user changes default search engine manually.

chrome/browser/protector/base_setting_change.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_PROTECTOR_BASE_SETTING_CHANGE_H_
 #define CHROME_BROWSER_PROTECTOR_BASE_SETTING_CHANGE_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/string16.h"
 
 class TemplateURL;
 
 namespace protector {
 
 class Protector;
 
 // Base class for setting change tracked by Protector.
 class BaseSettingChange {
  public:
   BaseSettingChange();
   virtual ~BaseSettingChange();
 
   // Applies initial actions to the setting if needed. Must be called before
-  // any other calls are made, including text getters. Returns true if
-  // initialization was successful.
+  // any other calls are made, including text getters.
+  // Returns true if initialization was successful. Otherwise, no other
+  // calls should be made.
+  // Associates this change with |protector_| instance so overrides must
+  // call the base method.

[whywhat, 2011/11/21 14:51:21]

This method cries to be a ctor...

[Ivan Korotkov, 2011/11/21 15:27:38]

Kind of, but it's called asynchronously (to reset default SE).
We can call pass Protector to the real ctor so there will be no need to call it
from base.

   virtual bool Init(Protector* protector);
 
   // Persists new setting if needed.
-  virtual void Apply(Protector* protector);
+  virtual void Apply();
 
   // Restores old setting if needed.
-  virtual void Discard(Protector* protector);
+  virtual void Discard();
+
+  // Called before the change is removed from the protector instance.
+  virtual void OnBeforeRemoved() = 0;
 
   // Returns the wrench menu item and bubble title.
   virtual string16 GetBubbleTitle() const = 0;
 
   // Returns the bubble message text.
   virtual string16 GetBubbleMessage() const = 0;
 
   // Returns text for the button to apply the change with |Apply|.
   // Returns empty string if no apply button should be shown.
   virtual string16 GetApplyButtonText() const = 0;
 
   // Returns text for the button to discard the change with |Discard|.
   virtual string16 GetDiscardButtonText() const = 0;
 
+  // Protector instance we've been associated with by an |Init| call.
+  Protector* protector() { return protector_; }
+
  private:
+  Protector* protector_;
+
   DISALLOW_COPY_AND_ASSIGN(BaseSettingChange);
 };
 
 // TODO(ivankr): CompositeSettingChange that incapsulates multiple
 // BaseSettingChange instances.
 
 // Allocates and initializes SettingChange implementation for default search
 // provider setting. Both |actual| and |backup| may be NULL if corresponding
 // values are unknown or invalid.
 BaseSettingChange* CreateDefaultSearchProviderChange(
     const TemplateURL* actual,
     const TemplateURL* backup);
 
 }  // namespace protector
 
 #endif  // CHROME_BROWSER_PROTECTOR_BASE_SETTING_CHANGE_H_